Draft-regulator.



H. B. HEMPHILL.

DRAFT REGULATOR. APPLIOATION FILED FEB. 10, 1908.

950 918 Patented Mar.1,1910.

3 SHEETS-SHEET 1.

85M; m coz ANDREW u. GRAHAM co. Punwumonumm WAQmum/w n H. B. HEMPHILL.

DRAFT REGULATOR.

' APPLICATION FILED F3110, 1908. 950,918. Patented Mar. 1,1910.

3 SHEETS-SHEET 2.

H. B. HEMPHILL.

DRAFT REGULATOR.

APPLICATION FILED FEB. m. 1908.

Patented Mar. 1, 1910.

3 SHEETS-SHEET 3.

o a o 0 Q1 0 O O 44 SM/WM/LMIZ: 52 w 777,ZI&/ZZ 33H f f f M munlw llGRAHAM c0. vucto-urolml'wina wssmmwu. D c,

STATES PATENT OFFICE.

HENRY B. HEMPI-IILL, OF ELDORADO, ILLINOIS, ASSIGNOR OF ONE-FOURTH TOGLEN A. SAPP AND CARL E. SAPP, OF WABASH COUNTY, ILLINOIS.

DRAFT-REGULATOR.

To all whom it may concern:

Be it known that I, HENRY B. HEMPHILL, a citizen of the United States,residing at Eldorado, in the county of Saline and State of Illinois,have invented certain new and useful Improvements in Draft-Regulators;and I do declare the following to be a full, clear, and exactdescription of the invention, such as will enable others skilled in theart to which it appertains to make and use the same.

My invention relates to draft regulators for boiler furnaces, and theobject of the invention is the provision of means which enables theengineer or operator to absolutely control the draft at all times so asto obtain maximum combustion for a given amount of fuel.

A further object of the invention is the provision of a device of thischaracter which enables me to secure a second combustion or, in otherwords, to continue the combustion or flame entirely through the boilertubes to the stack.

Further objects of the invention will appear as the specific descriptionwhich follows is read in connection with the accompanying drawings whichform a part of this specification, and in which,

Figure 1 is a front elevation of the furnace with the draft regulatingdevice, Fig. 2 is a side elevation thereof, Fig. 3 is a longitudinalsectional view with parts broken away. Fig. 4 is a horizontal sectionalview, Fig. 5 is a detail side elevation of the draft controlling fan,Fig. 6 is a sectional View of one of the retarding blades, and, Fig. 7is a front elevation of a modification.

Referring more especially to the drawings, 1 represents the front of thefurnace which is provided as usual with flue caps 2 and 3, and with theusual fire doors 4, and.

ash pit doors 5. The intermediate part of the boiler 6, is supported asis usual, and at its rear end upon a wall 8, which has formed in thelower part thereof an arch-way 9, and which permits the products ofcombustion to pass from the bridge wall to the rear end of the boiler tothe space 10, thereof which is formed between the walls 8 and 10. Sidewalls 12, inclose the boiler as is usual.

Leading from a point adjacent the stack 13, downwardly along the side ofthe boiler is an air inlet flue 14, having at its upper end a fan 15,and intermediate its length a Specification of Letters Patent.

Application filed February 10, 1908.

Patented Mar. 1, 1910. Serial No. 415,223.

damper 16, adapted to control the action of the fan and the steam jet,which will bev standing discharge nozzle 17, back of the i bridge Wall7. This nozzle is so positioned as to direct its output toward the rearof the furnace and in a direction with the normal draft so as to therebyincrease the combustion within the furnace.

The boiler is provided with the usual steam dome 18, and safety valve19. Leading from the steam dome is a pipe 20, having a discharge nozzle21, located within the air inlet flue 14, immediately below the fan 15,so as to direct the steam in a line with the draft of air so that itwill be properly comingled therewith. A suitable valve 22, is locatedbetween the steam dome and the 11ozzle so that the amount of steam fedto the draft tube may be properly regulated. In action the steam and airis projected violently from the nozzle 17, into the space between thewall 8 and bridge wall 7, and is thereby mixed with the unburned gasesso that they are ignited thereby causing a substantial secondcombustion, which in reality forms nothing more than a continuous flamefrom the fire box 23, to the rear end of the boiler 6. This flame is solong and well established that it passes entirely through the boilerbefore it dies out and thereby increasing the efficiency of the furnaceand producing more steam for the amount of coal used.

The damper 16, is used to regulate the force of the draft through theair inlet flue 14, but in order to more certainly accomplish thisresult, I arrange a draft regulating device in the shape of a fan 24,which is rotated by suction in the stack 13. I also provide means whichI shall hereinafter de scribe for rendering the action of this fanoperative or inoperative, as is desired. In order to regulate the actionof the draft regulating device 24, I attach two elongated retardingblades 25, to the shaft of the draft regulating device by couplin arms26, which are keyed to the shaft and are threaded upon their outer endsas at 27 to receive the tubular coupling member 28. This coupling memberis engaged at its opposite ends by an arm 29, upon which is threaded alock nut 30. It will be seen that by releasing the lock nut and turningthe blades, I am enabled to place them in such position that they willeither strike the air at an angle or will present a perfectly flat facethereto. WVhen in this latter position, the action of the regulatingdevice 2%, will, of course, be retarded and when in the former position,the action will be increased. By increasing or decreasing the action,the draft in the stack is either lessened or increased, thus regulatingthe draft as desired.

In order to obtain the maximum draft through the furnace the regulatingdevice is held stationary and the full head of steam allowed to passinto the air inlet flue 14, With the damper 16 wide open. Owing to thesmall amount of cool air passing into the stack at its base the hotgases rise in the stack by reason of the excessive combustion generated,and the draft is not retarded to any appreciable extent. The regulatingdevice is held stationary by means of a hook 32, pivotally carried by aneye 31, upon the stack and adapted to engage a similar eye on one of theretarding blades 25. hen it is desired to secure the minimum amount ofdraft the damper 16 is turned completely off, the steam is shut off fromthe draft flue 14, and the retarding blades turned edgewise so as topermit the suction in the stack to draw in cooIair and rotate theregulating device as fast as possible, the cool air entering retards theaction of the rising gases and thereby decreases the draft. Byregulating the angle of the retarding blades the fresh air admitted tothe stack at its base may be regulated.

In order to obtain a maximum draft through the stack by the manipulationof the regulating device 2& alone, it is only necessary to hold saiddevice stationary by means of the hook and eye 3132. This results in theminimum amount of fresh air entering the stack at its base thuspermitting the hot gases in the stack to rise in a substantiallyunobstructed manner. If it is desired to further increase the draftthrough the furnace the damper 16 may be opened and a jet of steam fromthe nozzle 21 forced into the pipe 22 thus sucking in a considerableamount of fresh air and forcing it out of the nozzle 17 behind thebridge wall. The minimum amount of draft through the furnace is obtainedby adjusting the retarding blades 25 so that their edges strike the airin their rotary movement and offer little resistance to the rotation ofthe regulating device 24. hen the regulating device is rotating at itshighest speed a relatively great amount of fresh air is permitted toenter the stack at its base on account of the. fact that the regulatingdevice olfers less resistance than when rotating at slower speeds. Thiscold air entering the stack nullities the effect of the rising gases andretards their action in proportion to the amount of air admitted whichis regulated, of course, by the speed of the regulating device 24governed by the position of the rotating blades In the modificationshown in Fig. 7 I have illustrated two furnaces A aml 15, arranged sideby side with a draft flue C, arranged intermediate the two steam domesof each by alve pipes (r, and with the space behind the bridge walls ofthe respective furnaces by pipes D, which are provided with dampers E.The flue is also provided with a damper F, so as to regulate the draftto the respec tive furnaces.

Having thus described my invention, what I claim and desire to secure byLetters latcut is:

1. In a furnace having a bridge wall. a draft line, a. discharge nozzleconnected with said line and opening into the space behind the bridgewall of the furnace, a steam jet projecting into said draft flue, meansto control the volume of draft through said flue, a stack having an airinlet aperture, a rotary regulating device carried by the stack forcontrolling the admission of fresh air through said aperture to thestack and thereby the draft through the furnace, means carried by androtating with said device for adjusting the action thereof, and means tohold said adjusting means stationary.

2. In a furnace having a bridge wall, a draft flue, a discharge nozzleconnected with said fine and opening into the space behind the bridgewall of the furnace, a steam jet projecting into said draft flue, meansto control the volume of draft through the line, a stack having an airinlet aperture, a rotary regulating device carried by the stack forcontrolling the admission of fresh air through the aperture to the stackand thereby the draft through the furnace, a pair of adjustable fanblades carried by the regulating device for controlling the action, andmeans to hold the fan blades in adjusted position.

I11 testimony whereof I have hereunto set my hand in presence of twosubscribing witnesses.

HENRY I). IIEMPIIILL.

Vitnesses PHILIP Vmsxorr, GLEN SAPP.

